Seizures in Dogs and Cats

What is a seizure?

A seizure (fit) is a complex series of events that originate in the front portion (motor cortex) of the brain. A group of nerve cells called neurones in this area suddenly produce an excessive amount of electrical activity which spreads through surrounding areas of the brain. This activity causes loss of control of bodily movements and functions, and sometimes loss of consciousness. Seizures may last between several seconds and several minutes. Convulsions can occasionally cause a loss of bowel, bladder, and vocal control (howling). Following a convulsion, the sufferer will often experience disorientation and drowsiness (occasionally aggression), and then eventually, recovery.

If your pet has a seizure, it could be a frightening experience for both of you. Seizures sometimes only occur once or twice in the animal’s life and cause no further problems. Other times, a seizure may be a sign of another disease or condition in the body. For a veterinarian to diagnose the cause, an examination and further testing will be required.

What causes seizures?

There are many causes which can be better explained by breaking them down into two distinct groups. The first group is ‘extra-cranial’, which means the seizure does not start from within the brain, but rather, from the rest of the body. An example of this is a seizure caused by an underlying condition like diabetes. The second group is ‘intra-cranial’ causes, where the seizure begins inside the brain. If your pet has had a seizure, your vet will begin by ruling out the ‘extra-cranial’ causes first. If no extra-cranial cause is identified, further tests will be needed to determine any inter-cranial causes.

Plan of action

If this is your pet’s first seizure, we will start with a normal clinical examination. If the cause is not discovered, we will run a series of blood tests. One of these tests require your pet to fast, so we may keep them in the clinic overnight. If the results from these tests do not reveal the cause, we will investigate if there are any intra-cranial causes, like meningitis or brain tumours. This is done by doing a ‘cerebral spinal fluid’ (CSF) exam, a ‘computed tomography (CT) scan, or a ‘magnetic resonance imaging (MRI) scan of the brain. For these tests, your animal needs to be anaesthetised. If these tests reveal no underlying disease, your pet may have the condition ‘epilepsy’.

What can be done?

Epilepsy treatments are usually effective if the condition is identified early enough. The more seizures your pet has before treatment is started, the more frequent those seizures will become. The brain becomes accustomed to the seizures occurring, and the nerve cells that create the impulses do it increasingly. It’s like muscle memory. Some cases of epilepsy can be unresponsive to treatment, meaning fits will occur more frequently, and new cell groups will also learn how to create seizures.

As every animal is different, the causes and severity of seizures will differ. Speaking with your Greencross Veterinary team will help you to better understand, diagnose, and create a treatment plan for your pet.